Graphene is an ideal candidate for such a composite structure due to its unparalleled carrier mobility. This allows for extremely enhanced and tunable electromagnetic response spectra when doped with other plasmonic materials, or fabricated as a component of a multilayer structure. Monolayer graphene has a response spectrum dominated by absorption peaks at \(\approx 4.5\,\) eV and \(\approx 15\,\) eV, the \(\pi \)  and \(\pi \)  + \(\sigma \)  surface plasmons. Graphene plasmon resonance provides low losses in the frequency regime below the optical phonon frequency of \(0.2\,\) eV, where large losses are typically present for metallic plasmonic materials. [1]}
